Motor Torque Control for Differential Speed Limiting in Vehicles
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Solution Overview
Problem
The use of limited slip differentials (LSD) in vehicles leads to significant wear and tear on electronic control actuators and clutches, resulting in a short service life and higher costs due to the need for frequent replacements.
Innovation Solution
A vehicle control method that adjusts the output torque of a motor based on wheel speed differences and slip rates to maintain a safe differential speed difference within a threshold, using a common differential without an electronic control actuator, thereby prolonging the differential's service life and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a limited slip differential (LSD) with electronic control actuator and clutch is used to control differential speed difference, then the differential speed difference can be limited within safety threshold, but the electronic control actuator and clutch suffer significant wear and tear leading to short service life and higher costs
Solution Approach 1:
The patent extracts and removes the electronic control actuator and clutch components from the differential system. Instead of using an LSD with these components, the invention uses a common differential without electronic control, thereby eliminating the wear and tear on these components while still achieving differential speed control through motor torque adjustment.
Solution Approach 2:
The patent replaces the mechanical control system (clutch and electronic control actuator) with an electric control system. The motor controller adjusts the output torque of the motor based on wheel speed differences and slip rates, substituting the mechanical friction-based differential control with an electric torque control mechanism.
2Reliability
If a limited slip differential (LSD) with electronic control actuator is used, then differential speed control is achieved, but the complexity of the system increases due to additional electronic control components
Solution Approach 1:
The patent removes the electronic control actuator and clutch components from the system, extracting only the essential function of differential speed control. The control logic is integrated into the existing motor controller, eliminating the need for separate electronic control hardware and reducing system complexity.
Solution Approach 2:
The motor controller is made multi-functional by enabling it to perform both motor control and differential speed control functions. The control unit uses the existing motor torque adjustment capability to achieve differential speed regulation, eliminating the need for dedicated electronic control components and reducing overall system complexity.
3Device complexity
If a common differential without electronic control is used, then system complexity is reduced and costs are lowered, but the differential speed difference cannot be controlled within safety threshold during high-speed cornering or off-road recovery
Solution Approach 1:
The patent implements a feedback control mechanism where the control unit continuously monitors wheel speeds and calculates slip rates. Based on this feedback, the motor controller dynamically adjusts the output torque to maintain differential speed difference within the safety threshold, enabling a common differential to achieve protected operation without electronic control actuators.
Solution Approach 2:
The patent changes the control parameter from mechanical torque distribution (in LSD) to electric torque adjustment. By dynamically adjusting the motor output torque based on real-time wheel speed and slip rate data, the system achieves differential speed control within safety thresholds while maintaining system simplicity and using a common differential.
Data Source
AI summary
A vehicle control method and apparatus, a vehicle, and a storage medium are disclosed, and relate to the field of automotive technologies. The method includes: obtaining wheel speeds of two wheels on a first drive shaft of a vehicle, where the first drive shaft is any drive shaft of the vehicle, and output torque of a first motor corresponding to the first drive shaft is first torque; and when a first difference between the two wheels on the first drive shaft is greater than a first safety threshold, controlling, based on slip rates of the two wheels on the first drive shaft, the output torque of the first motor to change from the first torque to second torque, so that the first difference between the two wheels on the first drive shaft is not greater than a second safety threshold.